US11940469B2 - Circuit system for measuring an electrical voltage - Google Patents
Circuit system for measuring an electrical voltage Download PDFInfo
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- US11940469B2 US11940469B2 US17/837,289 US202217837289A US11940469B2 US 11940469 B2 US11940469 B2 US 11940469B2 US 202217837289 A US202217837289 A US 202217837289A US 11940469 B2 US11940469 B2 US 11940469B2
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- switching element
- signal
- voltage
- circuit system
- conductive
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- 230000005669 field effect Effects 0.000 claims description 25
- 238000000034 method Methods 0.000 claims description 10
- 238000005259 measurement Methods 0.000 description 9
- 239000003990 capacitor Substances 0.000 description 6
- 208000028659 discharge Diseases 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 230000015654 memory Effects 0.000 description 2
- 230000032683 aging Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
Images
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16504—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the components employed
- G01R19/16519—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the components employed using FET's
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/2503—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques for measuring voltage only, e.g. digital volt meters (DVM's)
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/04—Voltage dividers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/10—Measuring sum, difference or ratio
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/165—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R19/16533—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application
- G01R19/16538—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application in AC or DC supplies
- G01R19/16542—Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values characterised by the application in AC or DC supplies for batteries
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/2506—Arrangements for conditioning or analysing measured signals, e.g. for indicating peak values ; Details concerning sampling, digitizing or waveform capturing
- G01R19/2509—Details concerning sampling, digitizing or waveform capturing
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
- G01R19/257—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques using analogue/digital converters of the type with comparison of different reference values with the value of voltage or current, e.g. using step-by-step method
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/378—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC] specially adapted for the type of battery or accumulator
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R31/392—Determining battery ageing or deterioration, e.g. state of health
Definitions
- the present invention relates to a circuit system for measuring an electrical voltage, in particular a battery voltage, and to a method for measuring an electrical voltage having such a circuit system.
- a resistance voltage divider is used that in some cases is also constructed having FET (field-effect transistor) switches in order to save idle current and in order to divide the voltage to the measurement area of the analog-digital converter (ADC) of a microcontroller.
- FET field-effect transistor
- the resistors also protect this measuring microcontroller against overvoltages by reducing the currents through the protective diodes.
- a capacitor before the ADC input stabilizes the measurement.
- a divider of 1:10 is assumed. In the worst case, it is 1:10.8.
- a minimum specified working voltage of 8 V has the result that the control device can discharge functions only starting from a measured voltage of 7.4 V.
- the energy reserve has to be correspondingly larger. Thus, it is appropriate to make a greater outlay for an accurate battery voltage measurement.
- the present invention provides a circuit system and a method for measuring an electrical voltage. Specific embodiments of the present invention result from the disclosure herein.
- the presented circuit system in accordance with the present invention is used to measure an electrical voltage, in particular a battery voltage.
- the circuit system is used for example in a motor vehicle, to measure the voltage of a battery used in the motor vehicle.
- the circuit system has a voltage divider, an integrating element, and an evaluating unit, the voltage divider receiving, at an input, a first signal that represents the electrical voltage to be measured, and having a first switching element and a second switching element, and being capable of assuming a first state, in which the first switching element is conductive and the second switching element is non-conductive, and a second state in which the first switching element is non-conductive and the second switching element is conductive, and outputting a second signal to an output that is situated between the first switching element and the second switching element.
- the voltage divider which can also be designated a time divider, is thus an element that is to be controlled in such a way that it can assume these two states.
- the controlling with suitable control signals thus enables a kind of clocked operation of this voltage divider, or time divider.
- the integrating element is designed to receive the second signal outputted by the voltage divider and to output a third signal that is correspondingly processed.
- the evaluation unit is set up to receive the third signal and to evaluate it in order to determine a value for the electrical voltage.
- the electrical voltage for example a battery voltage, can be determined very accurately, and thus measured.
- a field-effect transistor for example a MOSFET.
- Field-effect transistors are in wide distribution and are easily obtainable at low cost.
- a p-channel field-effect transistor can be used
- a first n-channel field-effect transistor can be used.
- a second n-channel field-effect transistor can be provided for controlling the p-channel field-effect transistor of the voltage divider.
- a field-effect transistor can be provided for the controlling of the two switching elements, or at least one of the two switching elements.
- an RC element can be used, realized as a low-pass filter.
- a comparator is provided as evaluation unit.
- an output of the comparator can be applied to a logical port that is applied to the voltage divider with a fixed clock pulse and in inverted fashion, so that the value of the electrical voltage is to be determined using a decimation filter.
- an analog-digital converter can be provided that accepts the third signal and a reference signal that represents a voltage reference, and compares the two signals to one another in order to determine the value for the electrical voltage to be measured.
- a voltage source can be provided in order to provide the voltage reference.
- a timer unit is provided in order to provide pulse-width-modulated signals (PWM) for controlling the switching elements.
- PWM pulse-width-modulated signals
- a microcontroller can be provided in which the timer unit is integrated.
- the ADC or, depending on the realization, the comparator can also be integrated in the microcontroller.
- a monitoring can be realized of a battery voltage and thus a battery voltage monitor can be realized, in particular for control devices having high power.
- the presented method is used to measure an electrical voltage, in particular a battery voltage, for example in a motor vehicle.
- the method is carried out using a circuit system of the type described herein.
- FIG. 1 shows, in a schematic diagram, a circuit system for carrying out an example embodiment of the method of the present invention.
- FIG. 2 shows, in a highly simplified fashion in a schematic representation, an example embodiment of the circuit system in accordance with the present invention.
- FIG. 3 shows a simplified schematic representation of a circuit system having a comparator for producing an output based on a comparison between a signal from a voltage divider and a reference voltage, according to an example embodiment of the present invention.
- FIG. 1 shows, in a schematic diagram, an embodiment of a circuit system for carrying out the presented method, designated as a whole by reference character 10 .
- the representation shows an input 12 for a battery voltage to be measured, a resistor R 2 14 of 20 kOhm and a second n-channel field-effect transistor 16 , a voltage divider 18 having a p-channel field-effect transistor Tp 20 and a first n-channel field-effect transistor Tn 22 , an RC element 24 having a resistor R 1 26 of 20 kOhm and a capacitor C 1 28 , and a microcontroller 30 .
- an ADC 32 and a timer unit 34 are provided in microcontroller 30 .
- Timer unit 34 outputs PWM signals 36 , 37 .
- ADC 34 has a first input 38 for receiving a voltage to be measured or evaluated, and a second input 40 for receiving a voltage reference provided by a voltage source 42 .
- Voltage divider 18 in circuit system 10 is realized through an intermittent connection to a voltage source to be measured and a reference ground.
- the following RC element 24 smooths the voltage, and also protects first input 38 of ADC 32 against excess currents.
- a highly accurate reference voltage, provided by voltage source 42 having small temperature tolerances is required. In this way, the tolerance of this measurement can be reduced to below 2%.
- the battery voltage to be measured is conducted via p-channel field-effect transistor Tp 20 to resistor R 1 26 , and to first n-channel field-effect transistor Tn 22 .
- First n-channel field-effect transistor Tn 22 then goes to ground.
- high-ohmic resistor R 1 26 can be connected in low-ohmic fashion to the voltage to be measured, as well as to ground.
- buffer capacitor C 1 28 having two functions, namely low-pass filter with R 1 26 and buffer capacitor for the following ADC 32 in microcontroller 30 .
- a pulse-width-modulated (PWM) signal 36 , 37 is required, and it has to be ensured that the two field-effect transistors 20 , 22 are never switched at the same time.
- PWM pulse-width-modulated
- the highly precise voltage reference is also measured in ADC 32 . If the two ADC values are set into relation, and this is multiplied by the voltage value of the reference and the divider ratio, the battery voltage value is obtained. Here the offset error of ADC 32 is also eliminated.
- the measurement accuracy can in addition be increased by applying the voltage value to capacitor C 1 28 , by modifying the PWM time divider ratio to be close to the voltage reference value. In this way, a large part of the ADC linearity error can be eliminated.
- FIG. 3 is a simplified illustration of an example embodiment of a comparator 71 of an evaluation unit 70 obtaining the output from the voltage divider 18 and from the voltage source 42 , and producing an output. The output of the comparator is then applied to a logical port. The port is read in with a fixed clock pulse, and is conducted in inverted fashion to the half-bridge formed by Tp 20 and Tn 22 . Using a decimation filter, the voltage value is then calculated. The group runtime of the decimation filter again yields an additional delay. Thus, care is to be taken that Tp 20 and Tn 22 form a half-bridge.
- An SD converter includes a so-called delta-sigma modulator that produces a bitstream, and a low-pass filter.
- the delta-signal modulation first fundamentally provides a coarse measurement of a signal.
- the resulting measurement error is integrated and is compensated for example via a counter-coupling.
- integrated modules are provided that have only one control input and that internally exclude the case of short-circuit in which both field-effect transistors are open. These are instead conceived as outputs with high current loads only if they can provide the maximum input voltage of 40 V. If a low-power half bridge for 40 V is present, this would thus be the ideal component.
- FIG. 2 shows, in highly simplified form, an embodiment of the presented circuit system, designated as a whole by reference character 50 .
- the representation shows a voltage divider 52 that includes a first switching element 54 and a second switching element 56 .
- a state is shown in which first switching element 54 is open, and is thus non-conductive, and second switching element 56 is closed and is thus conductive.
- a first signal 60 is received at an input 58 of voltage divider 52 .
- a second signal 64 is outputted at an output 62 of voltage divider 52 , which is situated between the two switching elements 54 , 56 .
- This second signal 64 is supplied to an integrating element 66 that in turn outputs a third signal 68 .
- This third signal 68 is evaluated by the evaluating unit 70 in order to determine the value of a voltage that is represented by first signal 60 .
- the presented method and the described circuit system can be used in particular in control devices that require a large amount of current and an energy reserve.
- a non-volatile memory to which information is written such as for example configuration, errors, and operating cycle, is typically provided in each larger control device.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
Description
(ON_Tn+ON_Tp)/ON_Tp.
Claims (11)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102021206219.9 | 2021-06-17 | ||
DE102021206219.9A DE102021206219A1 (en) | 2021-06-17 | 2021-06-17 | Circuit arrangement for measuring an electrical voltage |
Publications (2)
Publication Number | Publication Date |
---|---|
US20220404396A1 US20220404396A1 (en) | 2022-12-22 |
US11940469B2 true US11940469B2 (en) | 2024-03-26 |
Family
ID=84283768
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US17/837,289 Active US11940469B2 (en) | 2021-06-17 | 2022-06-10 | Circuit system for measuring an electrical voltage |
Country Status (3)
Country | Link |
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US (1) | US11940469B2 (en) |
CN (1) | CN115494292A (en) |
DE (1) | DE102021206219A1 (en) |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4560937A (en) * | 1981-11-16 | 1985-12-24 | Curtis Instruments, Inc. | Battery state of charge metering method and apparatus |
US5914606A (en) * | 1996-10-10 | 1999-06-22 | Becker-Irvin; Craig H. | Battery cell voltage monitor and method |
US6369576B1 (en) * | 1992-07-08 | 2002-04-09 | Texas Instruments Incorporated | Battery pack with monitoring function for use in a battery charging system |
US6992915B2 (en) * | 2002-03-27 | 2006-01-31 | Regents Of The University Of California | Self reverse bias low-power high-performance storage circuitry and related methods |
US8239148B2 (en) * | 2007-12-29 | 2012-08-07 | Hong Fu Jin Precision Industry (Shenzhen) Co., Ltd. | State switching device for switching states of electronic device by detecting battery voltage of the electronic device and method thereof |
US10345384B2 (en) * | 2016-03-03 | 2019-07-09 | Battelle Energy Alliance, Llc | Device, system, and method for measuring internal impedance of a test battery using frequency response |
-
2021
- 2021-06-17 DE DE102021206219.9A patent/DE102021206219A1/en active Pending
-
2022
- 2022-06-10 US US17/837,289 patent/US11940469B2/en active Active
- 2022-06-16 CN CN202210683719.4A patent/CN115494292A/en active Pending
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4560937A (en) * | 1981-11-16 | 1985-12-24 | Curtis Instruments, Inc. | Battery state of charge metering method and apparatus |
US6369576B1 (en) * | 1992-07-08 | 2002-04-09 | Texas Instruments Incorporated | Battery pack with monitoring function for use in a battery charging system |
US5914606A (en) * | 1996-10-10 | 1999-06-22 | Becker-Irvin; Craig H. | Battery cell voltage monitor and method |
US6992915B2 (en) * | 2002-03-27 | 2006-01-31 | Regents Of The University Of California | Self reverse bias low-power high-performance storage circuitry and related methods |
US8239148B2 (en) * | 2007-12-29 | 2012-08-07 | Hong Fu Jin Precision Industry (Shenzhen) Co., Ltd. | State switching device for switching states of electronic device by detecting battery voltage of the electronic device and method thereof |
US10345384B2 (en) * | 2016-03-03 | 2019-07-09 | Battelle Energy Alliance, Llc | Device, system, and method for measuring internal impedance of a test battery using frequency response |
Also Published As
Publication number | Publication date |
---|---|
US20220404396A1 (en) | 2022-12-22 |
CN115494292A (en) | 2022-12-20 |
DE102021206219A1 (en) | 2022-12-22 |
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